The United States has sanctioned Harakat Hezbollah al Nujaba, a radical Muslim militia group of about 10,0000 fighters, as well as its leader Akram Kaabi, the Treasury Department said on Tuesday.

Active in Iraq and Syria, Nujaba, which is known by various names including the “The Movement of the Noble Ones,” is also loyal to Iran. Reuters reported in 2017 that it was helping Tehran create a supply route through Iraq to Damascus, and its leaders have publicly acknowledged Iran’s support.

Washington’s concerns about the group are growing. In September Republican Senators David Perdue, Ted Cruz and Marco Rubio introduced the Iranian Proxies Terrorist Sanctions Act targeting it and another group. A bipartisan group in the House of Representatives in January then introduced companion legislation.

Kaabi is a cleric who was sanctioned by the US Treasury in 2008 for threatening the peace and stability of Iraq.